The present disclosure relates to a multilayer ceramic capacitor and a board having the same mounted thereon.
A multilayer ceramic capacitor, a multilayer chip electronic component, is a chip-type condenser commonly mounted on the circuit boards of various electronic products including display devices such as liquid crystal displays (LCDs), plasma display panels (PDPs), and the like, computers, smartphones, cellular phones, and the like, to charge and discharge electrical charges.
Multilayer ceramic capacitors may be used as components in various electronic devices, due to inherent advantages thereof, such as compactness, high degrees of capacitance, and ease of mountability.
A general multilayer ceramic capacitor may have a structure including a plurality of dielectric layers and internal electrodes, the internal electrodes having different polarities being alternately stacked with at least one dielectric layer interposed therebetween.
A power supply device for a central processing unit (CPU) of a computer, or the like, may have a problem in which voltage noise is generated due to rapid changes in a load current in the process of providing low voltage.
In this regard, multilayer capacitors have widely been used in power supply devices as decoupling capacitors for suppressing such voltage noise.
A multilayer ceramic capacitor for decoupling is required to have low equivalent series inductance (ESL) as an operation frequency is increased. Thus, research into reducing ESL levels in multilayer ceramic capacitors has been actively conducted.
Further, in order to supply power in a stable manner, a multilayer ceramic capacitor used for decoupling needs to control a level of equivalent series resistance (ESR).
In the case in which ESR of the multilayer ceramic capacitor is lower than a required level, an impedance peak at a parallel resonance frequency generated due to the ESL of the capacitor and plane capacitance of a micro processor package may increase, and impedance at a series resonance frequency of the capacitor may be excessively reduced.
Therefore, in order to allow a user to obtain flat impedance characteristics in a power distribution network, the ESR of the multilayer ceramic capacitor for decoupling should be easily controllable.
With regard to controlling ESR, the use of a material having a high degree of electrical resistance for external and internal electrodes may be considered. In this regard, changing the material of external and internal electrodes may provide high ESR while maintaining the related art low ESL structure.
However, in the case of using such a material having a high degree of electrical resistance for the external electrodes, a localized hot spot, caused by a current crowding phenomenon resulting from pin holes, may be generated. Further, in the case of using such a material having a high degree of electrical resistance for the internal electrodes, the material of the internal electrodes may be necessarily changed so that it can be matched with a ceramic material of the dielectric layers.
Therefore, since existing measures for controlling ESR have disadvantages as described above, research into a multilayer ceramic capacitor allowing for the controlling of ESR remains necessary.
In addition, in accordance with the recent trend for the rapid development of mobile terminals, such as tablet personal computers (PCs), Ultrabooks, and the like, microprocessors have also become miniaturized and highly integrated.
Therefore, areas of printed circuit boards have decreased, and mounting spaces for decoupling capacitors have been similarly limited, and thus, a multilayer ceramic capacitor capable of addressing the issue of limited mounting space remains in demand.